Abstract: Objective: We analyzed the lifecycle pattern and secondary production of FPOM feeding three dominant mayfly species from a tropical stream of Southern Eastern Ghats, India. Methodology: Month-wise sampling for a period of a year was done. The collected specimen were stored and reared. The size frequency and cohort production methods were used for analyzing life histories and secondary production. Results: The present study showed that C. alagarensis and L. silambarensis had asynchronous nymphal development with a continuous emergence in a year while, C. grimiensis had asynchronous pattern but mass emergence with two seasons. The cohort P/B ratio was analyzed for measuring secondary production. Conclusion: These findings address the need for more quantitative accounts of population dynamics (life cycle patterns, fecundity, development rates, production and P/B) of aquatic insect species in streams across environmental gradients.